The strip chart recorder, widely used for diagnostic display, is uneconomical in time and money. Thus, low-cost single channel electrocardiograms (ECG) units typically require 12 consecutive measurements with the appropriate labeling of each strip chart output (6 for extremities and 6 for chest leads). The more expensive multi-channel units save time in taking and labeling the strip chart output, but are considerably more expensive. Also, the strip chart output is often of such length that its storage is cumbersome.
In either the single channel or the multi-channel ECG units, the strip chart recorder utilizes mechanical means (motors, gears, etc.) to permanently record; thus, such units are susceptible to environmental influences, and are expensive to manufacture and maintain.